mygpo/users/subscriptions.py

   1 from mygpo.podcasts.models import Podcast
   2 from mygpo.history.stats import played_episode_counts
   3
   4
   5 class PodcastSorter(object):
   6     """Sorts a list of podcast"""
   7
   8     def __init__(self, podcasts):
   9         self.podcasts = podcasts
  10         self.sorted_podcasts = None
  11
  12     def _sort(self):
  13         return self.podcasts
  14
  15     def __len__(self):
  16         return len(self.podcasts)
  17
  18     def __getitem__(self, val):
  19         if self.sorted_podcasts is None:
  20             self.sorted_podcasts = self._sort()
  21
  22         return self.sorted_podcasts.__getitem__(val)
  23
  24     def __iter__(self):
  25         if self.sorted_podcasts is None:
  26             self.sorted_podcasts = self._sort()
  27
  28         return iter(self.sorted_podcasts)
  29
  30
  31 class PodcastPercentageListenedSorter(PodcastSorter):
  32     """Sorts podcasts by the percentage of listened episodes
  33
  34     Adds the attributes percent_listened and episodes_listened to the podcasts
  35
  36     Cost: 1 DB query"""
  37
  38     def __init__(self, podcasts, user):
  39         super(PodcastPercentageListenedSorter, self).__init__(podcasts)
  40         self.user = user
  41
  42     def _sort(self):
  43
  44         SORT_KEY = lambda podcast: podcast.percent_listened
  45
  46         counts = played_episode_counts(self.user)
  47         for podcast in self.podcasts:
  48             c = counts.get(podcast.id, 0)
  49             if podcast.episode_count:
  50                 podcast.percent_listened = c / float(podcast.episode_count)
  51                 podcast.episodes_listened = c
  52             else:
  53                 podcast.percent_listened = 0
  54                 podcast.episodes_listened = 0
  55
  56         return sorted(self.podcasts, key=SORT_KEY, reverse=True)
  57
  58
  59 def subscription_changes(device_id, podcast_states, since, until):
  60     """returns subscription changes for the device and podcast states"""
  61
  62     add, rem = [], []
  63     for p_state in podcast_states:
  64         change = p_state.get_change_between(device_id, since, until)
  65         if change == "subscribe":
  66             add.append(p_state.ref_url)
  67         elif change == "unsubscribe":
  68             rem.append(p_state.ref_url)
  69
  70     return add, rem
  71
  72
  73 def podcasts_for_states(podcast_states):
  74     """returns the podcasts corresponding to the podcast states"""
  75
  76     podcast_ids = [state.podcast for state in podcast_states]
  77     podcasts = Podcast.objects.filter(id__in=podcast_ids)
  78     podcasts = {podcast.id.hex: podcast for podcast in podcasts}
  79     return podcasts.values()